I was given an LED Cinema Display 1920x1200 from December 2008. I was able to fix a similar one because of a software issue on the owner's computer.
I was told that it was working intermittently, showing the computer screen and turning off soon aftewards. It stayed in a slightly damp basement for one year: when I opened it apart, it had a bit of mold on the metal.
I connected it to my mac computer and the display showed nothing. I took it apart and inspected the two boards, which seemed fine, although some of the metal on the power supply board had a layer of rust. I tightened the internal cable connections, left the cable for sensor-2 disconnected because it was too short to be connected when the screen was loose, and plugged it to power without a connection to a computer: the logic board whistled, had a spark, and produced smoke for a few seconds until I unplugged the power cable. I checked the logic board again and the damage was not apparent. I plugged the cable again, with no whistling, spark, or smoke this time, and connected the mini-display cable: the monitor displayed nothing but the fan was on high gear. I tried with several setups for the sensor-2 cable: disconnected, connected one way, and connected the other way. The result was the same: no display on the screen and high speed on the fan.
Does the whistling and the spark mean that one of the two boards is fried? If so, Apple has discontinued the product and does not seem to sell the parts, so I'd need to buy from a reseller with the risk of incompatibility. If so, Apple has discontinued the parts, so the cost and risk of second-hand parts to fix a 10-year old monitor seem large compared to the more modern options available.
The display is also missing a glass screen: does it play a role beyond aesthetics, e.g. in filtering UV from the backlit display?